Hardware Sequencing of Inflatable Nonlinear Actuators for Autonomous Soft Robots

Soft robots are an interesting alternative for classic rigid robots in appli-cations requiring interaction with organisms or delicate objects. Elastic inflatable actuators are one of the preferred actuation mechanisms for soft robots since they are intrinsically safe and soft. However, these pneumatic actuators each require a dedicated pressure supply and valve to drive and control their actuation sequence. Because of the relatively large size of pres-sure supplies and valves compared to electrical leads and electronic control-lers, tethering pneumatic soft robots with multiple degrees of freedom is bulky and unpractical. Here, a new approach is described to embed hardware intelligence in soft robots where multiple actuators are attached to the same pressure supply, and their actuation sequence is programmed by the inter-action between nonlinear actuators and passive flow restrictions. How to model this hardware sequencing is discussed, and it is demonstrated on an 8-degree-of-freedom walking robot where each limb comprises two actua-tors with a sequence embedded in their hardware. The robot is able to carry pay loads of 800 g in addition to its own weight and is able to walk at travel speeds of 3 body lengths per minute, without the need for complex on-board valves or bulky tethers.ERC starting gran

Complementary Platforms

We introduce an analytical framework close to the canonical model of platform competition investigated by Rochet and Tirole (2006) to study pricing decisions in two-sided markets when two or more platforms are needed simultaneously for the successful completion of a transaction. The model developed is a natural extension of the Cournot-Ellet theory of complementary monopoly featuring clear cut asymmetric single- and multihoming patterns across the market. The results indicate that the so-called anticommons problem generalizes to two-sided markets because individual platforms do not take into account the negative pricing externality they exert on the other platforms. As a result, mergers between such platforms may be welfare enhancing, but involve redistribution of surplus from one side of the market to the other. Moreover, the limit of an atomistic allocation of property rights however is not monopoly pricing, indicating that there also exist differences with the received theory of complementarity

Experiments on micro-milling of KDP crystal with micro ball-end mills

Potassium dihydrogen phosphate (KH2PO4 or KDP) crystal is an optical crystal and it has been widely used as frequency multiplication elements in inertial confinement fusion (ICF) research. Milling of the KDP crystal with a micro ball-end is difficult to achieve high-quality machined surface due to the soft-brittle property of the KDP crystal. The cutting force has been measured in the experiment and the Fast Fourier Transform (FFT) algorithm has been used to filter out the noises in the measured cutting force. The influence of the cutting parameters on the peak-valley value of the cutting force and the surface quality has been investigated. Based on the analysis of the P-V thrust force and the surface roughness Ra with respect to the cutting parameters, a relatively moderate feed rate and a large spindle speed are recommended for the micro-milling of KDP crystal.status: publishe

A self-regulating valve for single-phase liquid cooling of microelectronics

This paper reports on the design, optimization and testing of a self-regulating valve for single-phase liquid cooling of microelectronics. Its purpose is to maintain the integrated circuit (IC) at constant temperature and to reduce power consumption by diminishing flow generated by the pump as a function of the cooling requirements. It uses a thermopneumatic actuation principle that combines the advantages of zero power consumption and small size in combination with a high flow rate and low manufacturing costs. The valve actuation is provided by the thermal expansion of a liquid (actuation fluid) which, at the same time, actuates the valve and provides feed-back sensing. A maximum flow rate of 38 kg h-1 passes through the valve for a heat load up to 500 W. The valve is able to reduce the pumping power by up to 60% and it has the capability to maintain the IC at a more uniform temperature. © 2011 IOP Publishing Ltd

Characterization and control of a pneumatic microactuator with an integrated inductive position sensor

As the intelligence and the functionality of microrobots increase, there is a growing need to incorporate sensors into these robots. In order to limit the outer dimensions of these microsystems, this research investigates sensors that can be integrated efficiently into microactuators. Here, a pneumatic piston-cylinder microactuator with an integrated inductive position sensor was developed. The main advantage of pneumatic actuators is their high force and power density at microscale. The outside diameter of the actuator is 1.3 mm and the length is 15 mm. The stroke of the actuator is 12 mm, and the actuation force is 1 N at a supply pressure of 1.5 MPa. The position sensor consists of two coils wound around the cylinder of the actuator. The measurement principle is based on the change in coupling factor between the coils as the piston moves in the actuator. The sensor is extremely small since one layer of 25 μm copper wire is sufficient to achieve an accuracy of 10 μm over the total stroke. Position tests with a PI controller and a sliding mode controller showed that the actuator is able to position with an accuracy up to 30 μm. Such positioning systems offer great opportunities for all devices that need to control a large number of degrees of freedom in a restricted volume. © 2007 Elsevier B.V. All rights reserved

Chapter 5 - Electrochemical Based Hybrid Machining A2 - Luo, Xichun

Abstract The trend of product miniaturization, stringent metallurgical constraints, and advent of novel materials has necessitated development of hybrid electrochemical machining (ECM) processes. These hybrid ECM processes are under development with an aim to broaden the process capability and material processing window of existing ECM process or to assist other process energies. This chapter presents an overview of different types of electrochemical-based hybrid processes. Process fundamentals are discussed for each hybrid process. At the end of the chapter, a case study on ECM-based hybrid machining of titanium is presented.Abstract The trend of product miniaturization, stringent metallurgical constraints, and advent of novel materials has necessitated development of hybrid electrochemical machining (ECM) processes. These hybrid ECM processes are under development with an aim to broaden the process capability and material processing window of existing ECM process or to assist other process energies. This chapter presents an overview of different types of electrochemical-based hybrid processes. Process fundamentals are discussed for each hybrid process. At the end of the chapter, a case study on ECM-based hybrid machining of titanium is presented.status: publishe